1. Field of the Invention
The present invention relates to vehicle suspensions systems. More particularly, the present invention relates to acceleration sensitive damping arrangements suitable for use in vehicle dampeners (e.g., shock absorbers, struts, front forks).
2. Description of the Related Art
Inertia valves are utilized in vehicle shock absorbers in an attempt to sense instantaneous accelerations originating from a particular portion of the vehicle, or acting in a particular direction, and to alter the rate of damping accordingly. For example, the inertia valve may be configured to sense vertical accelerations originating at the sprung mass (e.g., the body of the vehicle) or at the unsprung mass (e.g., a wheel and associated linkage of the vehicle). Alternatively, the inertia valve may be configured to sense lateral accelerations of the vehicle.
Despite the apparent potential, and a long history of numerous attempts to utilize inertia valves in vehicle suspension, commercial inertia valve shock absorbers have enjoyed only limited success. Most attempted inertia valve shock absorbers have suffered from unresponsive or inconsistent operation due to undesired extraneous forces acting on the inertia valve. These extraneous forces may result from manufacturing limitations and/or external sources and often inhibit, or even prevent, operation of the inertia valve.
Further, there are currently no commercially available inertia valve shock absorbers for off-road bicycle, or mountain bike, applications. The problems associated with the use of inertia valves, mentioned above in relation to other vehicles, are magnified in the environment of lightweight vehicles and the relatively small size of mountain bike shock absorbers. Therefore, a need exists for an inertia valve shock absorber that can be commercially produced, and provides responsive, consistent performance without the problems associated with prior inertia valve designs.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener includes an inertia valve, comprising an inertia mass. The inertia mass is movable between a first position and a second position. In the first position, the valve substantially prevents fluid flow through the first flow circuit and in the second position, the valve permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener also includes an inertia valve, comprising an inertia mass, and a stop defining a socket for receiving the inertia mass. The inertia mass is movable between a first position and a second position. When the inertia mass is in the first position, the valve is spaced from the stop. The valve is configured to substantially prevent fluid flow through the first circuit when the mass is in the first position. When the inertia mass is in the second position, the valve abuts the stop and is at least partially positioned within the socket. The valve is configured to permit fluid flow through the first flow circuit when the mass is in the second position. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener further includes an inertia valve comprising an inertia mass. The inertia mass is movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further comprises a body including a portion which cooperates to exert a force on the inertia mass which delays the inertia mass from returning to the first position, wherein duration of such delay is independent of direction of movement of the piston.
A preferred embodiment is a method of dampening. The method includes providing an acceleration-sensitive dampener having a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener also includes a second chamber. A first flow circuit connects the first chamber and the second chamber. The dampener further includes an inertia valve comprising an inertia mass. The inertia mass is movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The method additionally includes applying an acceleration force to the inertia valve to move the inertia mass from the first position to the second position and to move the piston within the first chamber. The movement of the piston continuing until the piston completes a compression stroke. The method further includes delaying the inertia mass from returning to the first position until after a period of time after completion of the compression stroke.
A preferred embodiment is a method of dampening including selecting an acceleration threshold at which lower dampening is desired. The method additionally includes selecting a time interval during which it is desirable to maintain the lower dampening and providing a dampener having an acceleration responsive valve movable between a closed position and an open position. In the closed position the dampener provides a greater level of dampening and in the open position the dampener provides a lower level of dampening. The method further includes moving the dampener from the closed position to the open position in response to an acceleration force over the acceleration threshold and, after the valve is moved from the closed position to the open position, delaying the valve from returning to the closed position before completion of a dampener compression stroke and before the time interval elapses.
A preferred embodiment is a shock absorber including a first portion. The shock absorber also includes a valve moveable between a first position removed from the first portion and a second position contacting the first portion. One of the first portion and the valve defines a first surface. The other of the first portion and the valve includes a plurality of projections which cooperate with the first surface to define a contact surface area between the first portion and the valve when the first portion and the valve are in the second position. Further, the ratio of the mass of the valve to the contact surface area is at least 17 pounds per square inch.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener further includes an inertia valve, comprising an inertia mass movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber. The piston movement continues until the piston completes a compression stroke. The inertia valve further comprises a means for delaying the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener also includes an inertia valve, comprising an inertia mass and a stop defining a socket for receiving the inertia mass. The inertia mass is movable between a first position and a second position, wherein in the first position, the valve is spaced from the stop and is configured to substantially prevent fluid flow through the first circuit and in the second position, the valve abuts the stop and is at least partially positioned within the socket. The valve is configured to permit fluid flow through the first flow circuit when the mass is in the second position. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The dampener further includes a means for delaying the inertia mass from returning to the first position until a period of time after completion of the compression stroke.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener also includes an inertia valve, comprising an inertia mass movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The inertia mass moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The dampener further comprising means for delaying the inertia mass from returning to the first position, wherein duration of such delay is independent of direction of movement of the piston.
A preferred embodiment is an acceleration-sensitive dampener including a first section at least partially defining a first chamber and a second section comprising a piston. The piston is movable within the first chamber. The dampener defines a second chamber and includes a first flow circuit connecting the first chamber and the second chamber. The dampener includes an inertia valve, comprising an inertia mass movable between a first position wherein the valve substantially prevents fluid flow through the first flow circuit and a second position which permits fluid flow through the first circuit. The inertia valve moves between the first position and the second position in response to an acceleration force over a threshold. The acceleration force further causes the piston to move within the first chamber, the piston movement continuing until the piston completes a compression stroke. The inertia valve further includes a gripper which delays the inertia valve from returning to the first position until a period of time after both a last acceleration force over the threshold and completion of the compression stroke.
A preferred embodiment is a dampener including a first section and a second section. The first section at least partially defines a first chamber and the second section is movable with respect to the first section. A first flow circuit communicates with the first chamber. The dampener assembly also includes a first valve portion and a second valve portion. The first valve portion and second valve portion cooperate to define a first annular passage and a second annular passage. The first annular passage has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area. The second cross-sectional flow area is greater than the first cross-sectional flow area. The second annular passage has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area where the second cross-sectional flow area is greater than the first cross-sectional flow area. The first portion of the first and second annular passages are outward from the second portion. One of the first valve portion and the second valve portion defines an opening. The first valve portion and the second valve portion have a first position wherein the first portion of the first annular passage and the first portion of the second annular passage straddle the opening. The second portion of the first annular passage, the second portion of the second annular passage and the opening permit a first rate of flow through the opening. The first valve portion and the second valve portion also have a second position which permits a second rate of flow through the opening wherein the second rate of flow is greater than the first rate of flow.
A preferred embodiment is a dampener that includes a first section and a second section. The first section at least partially defines a first chamber. The second section is movable with respect to the first section. The dampener also includes a first flow circuit communicating with the first chamber. A first valve portion defines a first surface and a second valve portion defines a second surface, wherein the second surface faces the first surface. The second surface defines a first portion having a first section and a second section and a second portion having a first section and a second section. The first surface and the first section of the first portion of the second surface and the first surface and the first section of the second portion of the second surface define a first clearance distance when the first valve portion is centered with respect to the second valve portion. The first surface and the second section of the first portion of the second surface and the first surface and the second section of the second portion of the second surface defining a second clearance when the first valve portion is centered with respect to said second valve portion. Wherein further xc2xcxe2x89xa6(first clearance distance/second clearance distance) less than 1.
A preferred embodiment is a dampener as described in the paragraph above, wherein further ⅓xe2x89xa6(first clearance distance/second clearance distance) less than 1. A preferred embodiment is a dampener as described in the paragraph above, wherein further ⅖xe2x89xa6(first clearance distance/second clearance distance) less than 1. A preferred embodiment is a dampener as described in the paragraph above, wherein further xc2xdxe2x89xa6(first clearance distance/second clearance distance) less than 1. A preferred embodiment is a dampener as described in the paragraph above, wherein (first clearance distance)xe2x89xa60.0125 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (first clearance distance)xe2x89xa60.005 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (first clearance distance)xe2x89xa60.003 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (first clearance distance)xe2x89xa60.001 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (second clearance distancexe2x88x92first clearance distance)xe2x89xa70.0001 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (second clearance distancexe2x88x92first clearance distance)xe2x89xa70.001 inches. A preferred embodiment is a dampener as described in the paragraph above, wherein (second clearance distancexe2x88x92first clearance distance)xe2x89xa60.05 inches.
A preferred embodiment is a dampener assembly including a first section and a second section. The first section at least partially defines a first chamber. The second section includes a piston that is movable within the first chamber. The dampener assembly also includes a second chamber and a first flow circuit connecting the first chamber and the second chamber. An inertia valve is movable between a first position substantially preventing flow through the first flow circuit and a second position permitting flow through the first flow circuit. The inertia valve includes a first valve portion and a second valve portion. The first valve portion and the second valve portion cooperate to define a first annular passage and a second annular passage. The first annular passage has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area. The second cross-sectional flow area of the first annular passage is greater than the first cross-sectional flow area of the first annular passage. The second annular passage also has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area. The second cross-sectional flow area of the second annular passage is greater than the first cross-sectional flow area of the second annular passage. The first portions of the first annular passage and the second annular passage are outward from the second portions. One of the first valve portion and the second valve portion define an opening. The first valve portion and the second valve portion have a first position wherein the first portion of the first annular passage and the first portion of the second annular passage straddle the opening, wherein the second portion of the first annular passage, the second portion of the second annular passage and the opening permit a first rate of flow through the opening. The first valve portion and the second valve portion also have a second position which permits a second rate of flow through the opening wherein the second rate of flow is greater than the first rate of flow.
A preferred embodiment is a dampener assembly including a first section at least partially defining a chamber and a second section comprising a piston. The piston is movable within the chamber to create a compression fluid flow and a rebound fluid flow. The dampener assembly additionally includes an inertia valve movable along an axis, wherein no significant component of force is exerted on the inertia valve in a direction parallel to the axis due to either of the compression fluid flow and the rebound fluid flow.
A preferred embodiment is a bicycle dampener including a first section at least partially defining a first chamber and a second section movable with respect to the first section. A first flow circuit communicates with the first chamber. A first valve portion and a second valve portion cooperate to define a first annular passage and a second annular passage. The first annular passage has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area greater than the first cross-sectional flow area. The second annular passage has a first portion defining a first cross-sectional flow area and a second portion defining a second cross-sectional flow area greater than the first cross-sectional flow area. The first portions of the first annular passage and the second annular passage are outward from the second portions and one of the first valve portion and the second valve portion defining an opening. The first valve portion and the second valve portion have a first position wherein the first portion of the first annular passage and the first portion of the second annular passage straddle the opening. In the first position, the second portion of the first annular passage, the second portion of the second annular passage and the opening permitting a first rate of flow through the opening. In a second position of the first valve portion and the second valve portion, a second rate of flow through the opening greater than the first rate of flow is permitted.
A preferred embodiment is a bicycle dampener that includes a first section and a second section. The first section at least partially defines a first chamber. The second section is movable with respect to the first section. The dampener also includes a first flow circuit communicating with the first chamber. A first valve portion defines a first surface and a second valve portion defines a second surface, wherein the second surface faces the first surface. The second surface defines a first portion having a first section and a second section and a second portion having a first section and a second section. The first surface and the first section of the first portion of the second surface and the first surface and the first section of the second portion of the second surface define a first clearance distance when the first valve portion is centered with respect to the second valve portion. The first surface and the second section of the first portion of the second surface and the first surface and the second section of the second portion of the second surface define a second clearance when the first valve portion is centered with respect to said second valve portion. Fluid flow through the first clearance distance defines a first fluid velocity and fluid flow through the second clearance distance defines a second fluid velocity, wherein (second fluid velocity/first fluid velocity) is between 0.9 and 0.2.
A preferred embodiment is an inertia valve assembly including a first section and a second section. The inertia valve assembly also includes a first valve portion defining a first surface and a second valve portion defining a second surface. The second surface faces the first surface. The first surface and the second surface are configured to cooperate to form a flow path having varying cross-sectional areas, sized and shaped to produce, in the presence of flow through the flow path and forces tending to push the first valve portion off center with respect to the second valve portion, forces which tend to center the first valve portion with respect to the second valve portion.